The invention relates to fluid-tight pipe connections in which the ends of two pipes are clamped together and have facing joint faces around their respective bore orifices so as to extend perpendicularly to the said bore, there being at least one gasket ring surrounding the two orifices of the bores between the two joint surfaces.
The commonest type of pipe connection would appear to be a flange connection in which two mutually opposite ends of the pipes each have a flange whose face turned towards the other pipe is the joint face. The two flanges are clamped together by screws for example to hold a gasket between the joint faces.
However, conditions are often such that alignment of the two pipe ends is only possible using involved manufacturing operations. Although relatively thin or loosely supported pipes may as a rule be bent to such an extent that they are brought into alignment, in the case of short, squat or even block-like pipe terminations this is not possible.
Particular problems are likely in the case of pipe connections with an arcuate elbow pipe section intended to produce two joints at an angle to each other in automotive hydraulic circuitry, since in such a case space is at a premium and the joints have to withstand high pressures. Furthermore, the pipe connection is exposed to vibrations and the large tolerances allowed in automotive applications may not be reduced. For the connection together of such components at an angle to each other the possibility of using flexible hose is limited for it may not be sharply bent, is not available in large diameters with a high pressure resistance and furthermore owing to aggressive ambient conditions where the hose is used it has a short service life.
It is furthermore possible to employ a nipple or short length of pipe with two ball joints. The two ends of such a nipple (i.e. short length of pipe) may be aligned in relation to the opposite ends of the pipe so that a connection is produced between two connections requiring only a very short radius of bending. Such a connecting nipple is however complicated to produce, obstructs flow through the connection and tends to lead to leaks owing to the large number of joint surfaces.